3D Texturing: Undo.

Blender can only support a single undo system per undo step. As sculpting/vertex colors are mutual exclusive operations
out approach is just to switch the undo system when painting on an image.

PBVHNodes contain a list of areas that needs to be pushed to the undo system.

Currently the undo code is in sculpt_paint_image. We should eventually support undo for color filtering and other nodes.
we might need to place it to its own compile unit so more brushes can invoke the same code.

{F13048942}

Reviewed By: brecht

Maniphest Tasks: T97479

Differential Revision: https://developer.blender.org/D14821

2 files changed, 33 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_pbvh_pixels.hh b/source/blender/blenkernel/BKE_pbvh_pixels.hh
index fdfb5fa037e..e73950e6299 100644
--- a/source/blender/blenkernel/BKE_pbvh_pixels.hh
+++ b/source/blender/blenkernel/BKE_pbvh_pixels.hh
@@ -132,12 +132,22 @@ struct UDIMTilePixels {
   }
 };
 
+struct UDIMTileUndo {
+  short tile_number;
+  rcti region;
+
+  UDIMTileUndo(short tile_number, rcti &region) : tile_number(tile_number), region(region)
+  {
+  }
+};
+
 struct NodeData {
   struct {
     bool dirty : 1;
   } flags;
 
   Vector<UDIMTilePixels> tiles;
+  Vector<UDIMTileUndo> undo_regions;
   Triangles triangles;
 
   NodeData()
@@ -155,6 +165,23 @@ struct NodeData {
     return nullptr;
   }
 
+  void rebuild_undo_regions()
+  {
+    undo_regions.clear();
+    for (UDIMTilePixels &tile : tiles) {
+      rcti region;
+      BLI_rcti_init_minmax(&region);
+      for (PackedPixelRow &pixel_row : tile.pixel_rows) {
+        BLI_rcti_do_minmax_v(
+            &region, int2(pixel_row.start_image_coordinate.x, pixel_row.start_image_coordinate.y));
+        BLI_rcti_do_minmax_v(&region,
+                             int2(pixel_row.start_image_coordinate.x + pixel_row.num_pixels + 1,
+                                  pixel_row.start_image_coordinate.y + 1));
+      }
+      undo_regions.append(UDIMTileUndo(tile.tile_number, region));
+    }
+  }
+
   void mark_region(Image &image, const image::ImageTileWrapper &image_tile, ImBuf &image_buffer)
   {
     UDIMTilePixels *tile = find_tile_data(image_tile);
diff --git a/source/blender/blenkernel/intern/pbvh_pixels.cc b/source/blender/blenkernel/intern/pbvh_pixels.cc
index 40742ad36d5..49397797c0d 100644
--- a/source/blender/blenkernel/intern/pbvh_pixels.cc
+++ b/source/blender/blenkernel/intern/pbvh_pixels.cc
@@ -308,6 +308,12 @@ static void update_pixels(PBVH *pbvh, Mesh *mesh, Image *image, ImageUser *image
     apply_watertight_check(pbvh, image, image_user);
   }
 
+  /* Rebuild the undo regions. */
+  for (PBVHNode *node : nodes_to_update) {
+    NodeData *node_data = static_cast<NodeData *>(node->pixels.node_data);
+    node_data->rebuild_undo_regions();
+  }
+
   /* Clear the UpdatePixels flag. */
   for (PBVHNode *node : nodes_to_update) {
     node->flag = static_cast<PBVHNodeFlags>(node->flag & ~PBVH_RebuildPixels);